The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Hybrid vehicles are driven by multiple powerplants including, but not limited to an internal combustion engine and an electric machine. The electric machine functions as a motor/generator. In a generator mode, the electric machine is driven by the engine to generate electrical energy used to power electrical loads or charge batteries. In a motor mode, the electric machine supplements the engine, providing drive torque to drive the vehicle drivetrain.
Hybrid vehicles may include variable displacement and spark knock control systems. Spark knock control systems, such as Electronic Spark Control (ESC), detect spark knock and typically retard spark timing when spark knock is detected. Retarding the spark timing lowers engine torque output and decreases combustion efficiency. Variable displacement systems, such as Active Fuel Management (AFM), deactivate cylinders under low load conditions to improve fuel economy.